Gear transmission drive



ge an R. Williams.

ly 6, 1 s. 1.. CRAWSHAW ETAL 2,323,648

' GEAR TRANSMISSION DRIVE Filed Sept. 17, 1941 2 Sheets-Sheet l WITNESSES: INVENTORS tepbefll..&awabaw&

ATTORNEY July 1943- s. L. cRAwsHAw ETAL 2,323,648

GEAR TRANSMISSION DRIVE E i i nnnn-nglmnnn11 mlmmmmmnnnniifilnnqnnn kg 5 i WITNESSES: I INVENTORS W Stephen L.C ra ws}1aw 8 Jean R Wtllzams.

' ATTORNEY Patented July 6, 1943 UNITED STATES PATENT OFFICE GEAR TRANSMISSION DRIVE Pittsburgh, Pa., and Jean R. Williams, Seattle, Wash., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvama Application September 17, 1941, Serial No. 411,120

bearing clearances, housing elasticity, or foundation flexibility) will be equal in order to prevent the pinion-to-gear (or roll-to-roll) misalignment which would result if the deflections were unequal. I

It is also an object of our invention to provide a laterally flexible inner shaft as a means of connecting the overhung rotating load to the pinion shaft obviating the use for the same pur- Stephen L. Crawshaw,

2 Claims.

Our invention relates to gear transmission drives and more particularly to reduction gears and the shafts, bearings and other mountings for the'gears.

Our invention is of special utility in combination with ship propulsion drives and other drives, as rolling mill drives, where large amounts of power are to be transmitted.

In ship propulsion drives, and especially where electromagnetic couplings or hydraulic couplings pose of a rigid shaft and a torsionally and meare used, the proper distribution of the effects on chanically complicated flexible coupling. the housings is of primary importance. Another object of our invention is the pro- It is not practical to provide each of the two vision of a compact unitary rigid structure for a elements of an electromagnetic coupling or hyrelatively large gear transmission and its beardraulic C pl n With hearings on each side of ings mounted onamovable and somewhat flexible each element. This means that each element has base to prevent disalignment of the bearings. to be mounted on the stub end of an overhanging It 'is also an'object of our invention to provide shaft. a tapered torque shaft for the absorption of over- In a recent installation of our invention made hung load deflections without the introduction on board ship, the element of the clutch mounted of any complications in the torsional elastic on the stub-end of the overhanging shaft of the ystem. gear transmission weighs over twenty-five thou- A still further object of our invention is the sand pounds and is called upon to transmit over provision of changing the characteristics of an four thousand horsepower. elastic transmission system to avoid any reso- With prior art devices, the pinion driving the nance characteristics. gear coupled to the ship propeller has two bear- Other objects and advantages will become more ings one on each side of the pinion. This means apparent from a study'of the following specificathat the bearing, adjacent the magnetic coupling tion and the accompanying drawings, in which: element rigidly attached to the overhanging end Figure 1 is a plan view of a ship propulsion of the pinion shaft, has to carry not only pracdrive provided with our novel construction, and tically all the weight of the rotating portion of Fig. 2 is an enlarged sectional view on line the coupling, running into many tons, but also II-H of Fig. 1, of our invention, showing our half the weight of the pinion and half the gear contribution to the art.' and pinion reaction which, for the transmission In Fig. 1, the reference characters I and 2 of such l r e mo n s f p w r. i l of ndesignate Diesel engines or any other prime siderable value. The result is that the bearing mover for driving the inner'elements 3 and 4 of near the coupling is very much more loaded than electromagnetic couplings 5 and 6. The outer t e o e e resulting in unequal wear and elements I and 8 of the couplings are rigidly sethe danger of failure. cured to the thick ends of a pair of tapered shafts One object of our invention is the provision 4o 9 and I 0. of substantial equal loadings for the bearings of Coupled to these shafts, by our special cona gear transmission system. struction, are the pinions H and I2. These two It is an object of our invention to provide two pinions mesh with the main driving gear l3 for substantially separate means of support for the driving thepropeller I 4. With our arrangement coupling rotor and for the pinion shaft so that the bearings l5, ls, l1, l3, I9, 2!], 2i and 22 are the bearing, housing, or foundation deflections all subject to substantially the same load and are, resulting from the heavy overhung load will not therefore, alike in design so that just one type materially affect the positioning of the pinion of bearing need be built and kept in stock on shaft which is left substantiall free to position board ship for replacement. itself as its own loads and weights will deter- Fig. 2 shows in section on line 11-11 the armine. rangement and mounting of the element 1, shaft One object of our invention is the provision 9, and pinion H in the bearings for this element, of substantially equal loadings for the two pinion shaft, and pinion. It is, of course, understood shaft (or roll shaft) bearings so that the dethat the element 8, shaft l0, and pinion I 2 are flection of each end of the shaft (resulting from similarly mounted and a description and showing of the parts associated with one clutch element as 1 will suffice as a showing for the apparatus associated with element 8. Further, for the type of drive using but one engine, a single pinion drive will suffice and the elements as 2, 4, 6, 8, H3, l2, etc., would not have to be shown or described.

Our quill drive shown in Fig. 2 comprises preferably a tapered shaft (or a cylindrical shaft) having the outer element 1 of a magnetic coupling rigidly bolted to its right-hand thicker overhanging end. This element 1 may weigh many tons and it is thus important that the bearing 2| be not overloaded.

The tapered shaft 9 is mounted in the single bearing 2| and thus has a thick rigid right-hand overhanging portion 23 and a tapered longer and somewhat flexible left-hand overhanging portion 24. By means of a substantially rigid coupling 25, we rigidly couple a sleeve shaft or quill shaft 26, to the left-hand or thinner end of the shaft 9. The arrangement is such that the quill shaft 26 has an inner contour generally conforming to the shape of the tapered left-hand portion 24 but the coupling 25 holds the mately concentric of the shaft 9 and in spaced relation thereto.

The quill shaft is of sufficient length to terminate adjacent the bearing 2|. The quill shaft 26 is mounted in two bearings l5 and 18, the bearing !5 being just inside the coupling 25 and thus near the left-hand end of the quill shaft, and the bearing l8 being at the right-hand end of the quill shaft and right adjacent the bearing 2|.

The coupling face of the main gear housing 29 may thus be readily removed and altered in weight and rigidity to effectively counteract any critical operating conditions of the engine system. That is, if for a given construction of ship hull, gear housing, and engine vibrations, resonance frequencies occur the size (weight) and rigidity may be changed to avoid such resonance.

The pinion H is rigidly mounted on the midportion of sleeve 28 or may be made, as shown, an integral part of the sleeve. The pinion H meshes with gear l3 to driv a load as a ship propeller.

With our arrangement, the bearings for the pinion are relieved of the overhung element 1 of the coupling. The inner shaft 9 is balanced on a single bearing 2| and this bearing is subject to the coupling weight only. This inner shaft 9 transmits the torque and only a small part of the overhung load of coupling 25 to the outer or quill shaft 26. This outer or quill shaft, being practically free of the coupling weight reaction, is of substantially balanced design. That is to say, the tooth loads and the weights are equally divided between the two pinion bearings I5 and I8 which are of the same size. There is thus no tendency of the pinion shaft to cock in its bearings and produce a misalignment in the tooth contact region.

Our quill drive possesses many advantage over prior art drives. It is simpler and more compact. The cumbersome and complicated expensive flexible coupling needed with prior art devices is eliminated. The flexibility required to allow the pinion shaft to align itself independently of the coupling shaft is provided by th flexible inner shaft instead of a flexible coupling. Only three quill shaft approxi- 25 being at the left-hand outer element 1 through the rigid bearings are used and these are all in line, are all of the same size and design, and are mounted in the same rigid housing. The simple machining operations required for the three bearing bores eliminates the need for any complicated aligning arrangement.

We claim as our invention:

1. In a transmission gear, in combination, a shaft, being thick and rigid and of a given uniform diameter for a relatively short length near one end and being of lesser and lesser diameter in the direction of the other end whereby the shaft is progressively more flexible in the direction of the thinner end, one bearing for the shaft 50 disposed about the said thick uniform diameter portion of the shaft that a short rigid stub portion extends from one side of the bearing and that the thinner flexible end extends a relatively greater distance from the other side of the bearing, a relatively heavy driving clutch member car- .ried by the said stub portion, said bearing constituting the sole support for said driving member, a comparatively rigid quill shaft disposed over the shaft and coupling means at one of its ends for rigidly so connecting over the quill shaft to the thinner flexible end of the shaft that the quill shaft is spaced from the shaft, the length of the quill shaft being such that its other or free end is adjacent the bearing and the outer diameter of the quill shaft at each end thereof and for a relatively short axial length thereof being equal to said given uniform diameter of the shaft, two bearings, each exactly like said one bearing so that the parts of all the bearings are interchangeable, for the quill shaft, one of said two bearings being disposed at the free end of the quill shaft adjacent the said one bearing and the other of said two bearing being disposed just inside the coupling between the quill shaft and the shaft, and a pinion on the quill shaft between the two bearings.

2.111 a transmission gear, in combination, a shaft being thick and rigid and of a given uniform diameter for a relatively short length near one end and being of a lesser diameter in the direction of the other end whereby the shaft is more flexible in the direction of the thinner end, one bearing for the shaft so disposed about the said thick uniform diameter portion of the shaft that a short rigid stub portion extends from one side of the bearing and that the thinner flexible end extends a relatively greater distance from the other side of the bearing, a relatively heavy driving clutch member carried by the said stub portion, said bearing constituting the sole support for said driving member, a comparatively rigid quill shaft disposed over the shaft and coupling means at one of its ends for rigidly so connecting over the quill shaft to the thinner flexible end of the shaft, that the quill shaft is spaced from the shaft, the length of the quill shaft being such that its other or free end is adjacent said bearing, two bearings for the quill shaft, one of said two bearings being disposed at the free end of the quill shaft adjacent the said one bearing and the other of said two bearings being disposed just inside the coupling between the quill shaft and the shaft, and a pinion on the quill shaft between the two bearings.

STEPHEN L. CRAWSHAW. JEAN R. WILLIAMS. 

